China’s Tianzhou 1 freighter, a pathfinder for regular resupply and refueling trips to the country’s planned space station, wrapped up a series of successful propellant transfer tests with the orbiting Tiangong 2 space lab Saturday and detached from the module for more standalone experiments and a destructive re-entry into Earth’s atmosphere.

A series of achievements in China’s space program over the last 12 months have set the stage to start construction of the country’s first space station in 2019, a year later than previously scheduled, officials said Friday.

The robotic Tianzhou 1 refueling freighter launched last week has successfully completed the first in-orbit propellant transfer with China’s Tiangong 2 space lab, a major accomplishment as the country’s engineers hope to finish assembly of a large space station by 2022, officials said Thursday.

Less than two days after launching from southern China, the Tianzhou 1 supply ship glided to an automated linkup with the Chinese Tiangong 2 space laboratory around 240 miles above Earth on Saturday, ready for several months of technical demonstrations to prepare for assembly of a space station in the next few years.

A Long March 7 rocket lifted off Thursday with Tianzhou 1, an unpiloted refueling freighter heading for China’s Tiangong 2 mini-space station to conduct several months of robotic demonstrations, practicing for the assembly and maintenance of a future permanently-staffed orbital research complex.

Chinese engineers rolled out a Long March 7 rocket to a seaside launch complex on Hainan Island in the South China Sea on Monday, aiming to fire a robotic refueling freighter into orbit as soon as Thursday to test technology for China’s future space station.